Test for latitudinal variation of life history, behavior and mortality in the strictly univoltine damselfly Sympecma fusca (Zygoptera: Lestidae)

Abstract

A wealth of evidence shows that combinations of ecological stressors interact in shaping life history traits, but little is known about how ecological stressors combine with different seasonal time constraints to shape life history, behavior and mortality across populations. We studied life history, behavior and mortality rate in two latitudinally distant populations of the strictly univoltine, adult-overwintering damselfly Sympecma fusca. Results from laboratory common-garden and outdoor experiments indicated countergradient variation of larval development time and growth rate: the more time-constrained larvae showed faster development and a higher growth rate. This finding led to larger size at emergence in the more time-constrained individuals. Under conditions of intraspecific interaction (outdoor experiment), northern individuals showed lower survival than southern ones, presumably due to cannibalism. In the absence of intraspecific interactions (laboratory experiment), northern and southern larvae did not differ in survival. Finally, laboratory-grown northern and southern larvae did not differ in activity level. This is the first time that compensation for seasonal time constraints has been shown in a temperate odonate species that overwinters in the adult stage.